lib/socks_gssapi.c

   1 /***************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
   4  *                             / __| | | | |_) | |
   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  * Copyright (C) 2009, 2011, Markus Moeller, <markus_moeller@compuserve.com>
   9  *
  10  * This software is licensed as described in the file COPYING, which
  11  * you should have received as part of this distribution. The terms
  12  * are also available at http://curl.haxx.se/docs/copyright.html.
  13  *
  14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  15  * copies of the Software, and permit persons to whom the Software is
  16  * furnished to do so, under the terms of the COPYING file.
  17  *
  18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19  * KIND, either express or implied.
  20  *
  21  ***************************************************************************/
  22
  23 #include "setup.h"
  24
  25 #ifndef CURL_DISABLE_PROXY
  26
  27 #ifdef HAVE_GSSAPI
  28 #ifdef HAVE_OLD_GSSMIT
  29 #define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
  30 #endif
  31 #ifndef gss_nt_service_name
  32 #define gss_nt_service_name GSS_C_NT_HOSTBASED_SERVICE
  33 #endif
  34 #include <string.h>
  35
  36 #ifdef HAVE_STDLIB_H
  37 #include <stdlib.h>
  38 #endif
  39
  40 #include "gssapi.h"
  41 #include "urldata.h"
  42 #include "sendf.h"
  43 #include "connect.h"
  44 #include "timeval.h"
  45 #include "socks.h"
  46 #include "warnless.h"
  47
  48 #define _MPRINTF_REPLACE /* use our functions only */
  49 #include <curl/mprintf.h>
  50
  51 #include "curl_memory.h"
  52 /* The last #include file should be: */
  53 #include "memdebug.h"
  54
  55 static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;
  56
  57 /*
  58  * Helper gssapi error functions.
  59  */
  60 static int check_gss_err(struct SessionHandle *data,
  61                          OM_uint32 major_status,
  62                          OM_uint32 minor_status,
  63                          const char* function)
  64 {
  65   if(GSS_ERROR(major_status)) {
  66     OM_uint32 maj_stat,min_stat;
  67     OM_uint32 msg_ctx = 0;
  68     gss_buffer_desc status_string;
  69     char buf[1024];
  70     size_t len;
  71
  72     len = 0;
  73     msg_ctx = 0;
  74     while(!msg_ctx) {
  75       /* convert major status code (GSS-API error) to text */
  76       maj_stat = gss_display_status(&min_stat, major_status,
  77                                     GSS_C_GSS_CODE,
  78                                     GSS_C_NULL_OID,
  79                                     &msg_ctx, &status_string);
  80       if(maj_stat == GSS_S_COMPLETE) {
  81         if(sizeof(buf) > len + status_string.length + 1) {
  82           strcpy(buf+len, (char*) status_string.value);
  83           len += status_string.length;
  84         }
  85         gss_release_buffer(&min_stat, &status_string);
  86         break;
  87       }
  88       gss_release_buffer(&min_stat, &status_string);
  89     }
  90     if(sizeof(buf) > len + 3) {
  91       strcpy(buf+len, ".\n");
  92       len += 2;
  93     }
  94     msg_ctx = 0;
  95     while(!msg_ctx) {
  96       /* convert minor status code (underlying routine error) to text */
  97       maj_stat = gss_display_status(&min_stat, minor_status,
  98                                     GSS_C_MECH_CODE,
  99                                     GSS_C_NULL_OID,
 100                                     &msg_ctx, &status_string);
 101       if(maj_stat == GSS_S_COMPLETE) {
 102         if(sizeof(buf) > len + status_string.length)
 103           strcpy(buf+len, (char*) status_string.value);
 104         gss_release_buffer(&min_stat, &status_string);
 105         break;
 106       }
 107       gss_release_buffer(&min_stat, &status_string);
 108     }
 109     failf(data, "GSSAPI error: %s failed:\n%s\n", function, buf);
 110     return(1);
 111   }
 112
 113   return(0);
 114 }
 115
 116 CURLcode Curl_SOCKS5_gssapi_negotiate(int sockindex,
 117                                       struct connectdata *conn)
 118 {
 119   struct SessionHandle *data = conn->data;
 120   curl_socket_t sock = conn->sock[sockindex];
 121   CURLcode code;
 122   ssize_t actualread;
 123   ssize_t written;
 124   int result;
 125   long timeout;
 126   OM_uint32 gss_major_status, gss_minor_status, gss_status;
 127   OM_uint32 gss_ret_flags;
 128   int gss_conf_state, gss_enc;
 129   gss_buffer_desc  service = GSS_C_EMPTY_BUFFER;
 130   gss_buffer_desc  gss_send_token = GSS_C_EMPTY_BUFFER;
 131   gss_buffer_desc  gss_recv_token = GSS_C_EMPTY_BUFFER;
 132   gss_buffer_desc  gss_w_token = GSS_C_EMPTY_BUFFER;
 133   gss_buffer_desc* gss_token = GSS_C_NO_BUFFER;
 134   gss_name_t       server = GSS_C_NO_NAME;
 135   gss_name_t       gss_client_name = GSS_C_NO_NAME;
 136   unsigned short   us_length;
 137   char             *user=NULL;
 138   unsigned char socksreq[4]; /* room for gssapi exchange header only */
 139   char *serviceptr = data->set.str[STRING_SOCKS5_GSSAPI_SERVICE];
 140
 141   /* get timeout */
 142   timeout = Curl_timeleft(data, NULL, TRUE);
 143
 144   /*   GSSAPI request looks like
 145    * +----+------+-----+----------------+
 146    * |VER | MTYP | LEN |     TOKEN      |
 147    * +----+------+----------------------+
 148    * | 1  |  1   |  2  | up to 2^16 - 1 |
 149    * +----+------+-----+----------------+
 150    */
 151
 152   /* prepare service name */
 153   if(strchr(serviceptr,'/')) {
 154     service.value = malloc(strlen(serviceptr));
 155     if(!service.value)
 156       return CURLE_OUT_OF_MEMORY;
 157     service.length = strlen(serviceptr);
 158     memcpy(service.value, serviceptr, service.length);
 159
 160     gss_major_status = gss_import_name(&gss_minor_status, &service,
 161                                        (gss_OID) GSS_C_NULL_OID, &server);
 162   }
 163   else {
 164     service.value = malloc(strlen(serviceptr) +strlen(conn->proxy.name)+2);
 165     if(!service.value)
 166       return CURLE_OUT_OF_MEMORY;
 167     service.length = strlen(serviceptr) +strlen(conn->proxy.name)+1;
 168     snprintf(service.value, service.length+1, "%s@%s",
 169              serviceptr, conn->proxy.name);
 170
 171     gss_major_status = gss_import_name(&gss_minor_status, &service,
 172                                        gss_nt_service_name, &server);
 173   }
 174
 175   gss_release_buffer(&gss_status, &service); /* clear allocated memory */
 176
 177   if(check_gss_err(data,gss_major_status,
 178                    gss_minor_status,"gss_import_name()")) {
 179     failf(data, "Failed to create service name.");
 180     gss_release_name(&gss_status, &server);
 181     return CURLE_COULDNT_CONNECT;
 182   }
 183
 184   /* As long as we need to keep sending some context info, and there's no  */
 185   /* errors, keep sending it...                                            */
 186   for(;;) {
 187     gss_major_status = Curl_gss_init_sec_context(&gss_minor_status,
 188                                                  GSS_C_NO_CREDENTIAL,
 189                                                  &gss_context, server,
 190                                                  GSS_C_NULL_OID,
 191                                                  GSS_C_MUTUAL_FLAG |
 192                                                  GSS_C_REPLAY_FLAG,
 193                                                  0,
 194                                                  NULL,
 195                                                  gss_token,
 196                                                  NULL,
 197                                                  &gss_send_token,
 198                                                  &gss_ret_flags,
 199                                                  NULL);
 200
 201     if(gss_token != GSS_C_NO_BUFFER)
 202       gss_release_buffer(&gss_status, &gss_recv_token);
 203     if(check_gss_err(data,gss_major_status,
 204                      gss_minor_status,"gss_init_sec_context")) {
 205       gss_release_name(&gss_status, &server);
 206       gss_release_buffer(&gss_status, &gss_recv_token);
 207       gss_release_buffer(&gss_status, &gss_send_token);
 208       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 209       failf(data, "Failed to initial GSSAPI token.");
 210       return CURLE_COULDNT_CONNECT;
 211     }
 212
 213     if(gss_send_token.length != 0) {
 214       socksreq[0] = 1;    /* gssapi subnegotiation version */
 215       socksreq[1] = 1;    /* authentication message type */
 216       us_length = htons((short)gss_send_token.length);
 217       memcpy(socksreq+2,&us_length,sizeof(short));
 218
 219       code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 220       if((code != CURLE_OK) || (4 != written)) {
 221         failf(data, "Failed to send GSSAPI authentication request.");
 222         gss_release_name(&gss_status, &server);
 223         gss_release_buffer(&gss_status, &gss_recv_token);
 224         gss_release_buffer(&gss_status, &gss_send_token);
 225         gss_delete_sec_context(&gss_status, &gss_context, NULL);
 226         return CURLE_COULDNT_CONNECT;
 227       }
 228
 229       code = Curl_write_plain(conn, sock, (char *)gss_send_token.value,
 230                               gss_send_token.length, &written);
 231
 232       if((code != CURLE_OK) || ((ssize_t)gss_send_token.length != written)) {
 233         failf(data, "Failed to send GSSAPI authentication token.");
 234         gss_release_name(&gss_status, &server);
 235         gss_release_buffer(&gss_status, &gss_recv_token);
 236         gss_release_buffer(&gss_status, &gss_send_token);
 237         gss_delete_sec_context(&gss_status, &gss_context, NULL);
 238         return CURLE_COULDNT_CONNECT;
 239       }
 240
 241     }
 242
 243     gss_release_buffer(&gss_status, &gss_send_token);
 244     gss_release_buffer(&gss_status, &gss_recv_token);
 245     if(gss_major_status != GSS_S_CONTINUE_NEEDED) break;
 246
 247     /* analyse response */
 248
 249     /*   GSSAPI response looks like
 250      * +----+------+-----+----------------+
 251      * |VER | MTYP | LEN |     TOKEN      |
 252      * +----+------+----------------------+
 253      * | 1  |  1   |  2  | up to 2^16 - 1 |
 254      * +----+------+-----+----------------+
 255      */
 256
 257     result=Curl_blockread_all(conn, sock, (char *)socksreq, 4,
 258                               &actualread, timeout);
 259     if(result != CURLE_OK || actualread != 4) {
 260       failf(data, "Failed to receive GSSAPI authentication response.");
 261       gss_release_name(&gss_status, &server);
 262       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 263       return CURLE_COULDNT_CONNECT;
 264     }
 265
 266     /* ignore the first (VER) byte */
 267     if(socksreq[1] == 255) { /* status / message type */
 268       failf(data, "User was rejected by the SOCKS5 server (%d %d).",
 269             socksreq[0], socksreq[1]);
 270       gss_release_name(&gss_status, &server);
 271       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 272       return CURLE_COULDNT_CONNECT;
 273     }
 274
 275     if(socksreq[1] != 1) { /* status / messgae type */
 276       failf(data, "Invalid GSSAPI authentication response type (%d %d).",
 277             socksreq[0], socksreq[1]);
 278       gss_release_name(&gss_status, &server);
 279       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 280       return CURLE_COULDNT_CONNECT;
 281     }
 282
 283     memcpy(&us_length, socksreq+2, sizeof(short));
 284     us_length = ntohs(us_length);
 285
 286     gss_recv_token.length=us_length;
 287     gss_recv_token.value=malloc(us_length);
 288     if(!gss_recv_token.value) {
 289       failf(data,
 290             "Could not allocate memory for GSSAPI authentication "
 291             "response token.");
 292       gss_release_name(&gss_status, &server);
 293       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 294       return CURLE_OUT_OF_MEMORY;
 295     }
 296
 297     result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 298                               gss_recv_token.length,
 299                               &actualread, timeout);
 300
 301     if(result != CURLE_OK || actualread != us_length) {
 302       failf(data, "Failed to receive GSSAPI authentication token.");
 303       gss_release_name(&gss_status, &server);
 304       gss_release_buffer(&gss_status, &gss_recv_token);
 305       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 306       return CURLE_COULDNT_CONNECT;
 307     }
 308
 309     gss_token = &gss_recv_token;
 310   }
 311
 312   gss_release_name(&gss_status, &server);
 313
 314   /* Everything is good so far, user was authenticated! */
 315   gss_major_status = gss_inquire_context (&gss_minor_status, gss_context,
 316                                           &gss_client_name, NULL, NULL, NULL,
 317                                           NULL, NULL, NULL);
 318   if(check_gss_err(data,gss_major_status,
 319                    gss_minor_status,"gss_inquire_context")) {
 320     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 321     gss_release_name(&gss_status, &gss_client_name);
 322     failf(data, "Failed to determine user name.");
 323     return CURLE_COULDNT_CONNECT;
 324   }
 325   gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
 326                                       &gss_send_token, NULL);
 327   if(check_gss_err(data,gss_major_status,
 328                    gss_minor_status,"gss_display_name")) {
 329     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 330     gss_release_name(&gss_status, &gss_client_name);
 331     gss_release_buffer(&gss_status, &gss_send_token);
 332     failf(data, "Failed to determine user name.");
 333     return CURLE_COULDNT_CONNECT;
 334   }
 335   user=malloc(gss_send_token.length+1);
 336   if(!user) {
 337     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 338     gss_release_name(&gss_status, &gss_client_name);
 339     gss_release_buffer(&gss_status, &gss_send_token);
 340     return CURLE_OUT_OF_MEMORY;
 341   }
 342
 343   memcpy(user, gss_send_token.value, gss_send_token.length);
 344   user[gss_send_token.length] = '\0';
 345   gss_release_name(&gss_status, &gss_client_name);
 346   gss_release_buffer(&gss_status, &gss_send_token);
 347   infof(data, "SOCKS5 server authencticated user %s with gssapi.\n",user);
 348   free(user);
 349   user=NULL;
 350
 351   /* Do encryption */
 352   socksreq[0] = 1;    /* gssapi subnegotiation version */
 353   socksreq[1] = 2;    /* encryption message type */
 354
 355   gss_enc = 0; /* no data protection */
 356   /* do confidentiality protection if supported */
 357   if(gss_ret_flags & GSS_C_CONF_FLAG)
 358     gss_enc = 2;
 359   /* else do integrity protection */
 360   else if(gss_ret_flags & GSS_C_INTEG_FLAG)
 361     gss_enc = 1;
 362
 363   infof(data, "SOCKS5 server supports gssapi %s data protection.\n",
 364         (gss_enc==0)?"no":((gss_enc==1)?"integrity":"confidentiality"));
 365   /* force for the moment to no data protection */
 366   gss_enc = 0;
 367   /*
 368    * Sending the encryption type in clear seems wrong. It should be
 369    * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
 370    * The NEC reference implementations on which this is based is
 371    * therefore at fault
 372    *
 373    *  +------+------+------+.......................+
 374    *  + ver  | mtyp | len  |   token               |
 375    *  +------+------+------+.......................+
 376    *  + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
 377    *  +------+------+------+.......................+
 378    *
 379    *   Where:
 380    *
 381    *  - "ver" is the protocol version number, here 1 to represent the
 382    *    first version of the SOCKS/GSS-API protocol
 383    *
 384    *  - "mtyp" is the message type, here 2 to represent a protection
 385    *    -level negotiation message
 386    *
 387    *  - "len" is the length of the "token" field in octets
 388    *
 389    *  - "token" is the GSS-API encapsulated protection level
 390    *
 391    * The token is produced by encapsulating an octet containing the
 392    * required protection level using gss_seal()/gss_wrap() with conf_req
 393    * set to FALSE.  The token is verified using gss_unseal()/
 394    * gss_unwrap().
 395    *
 396    */
 397   if(data->set.socks5_gssapi_nec) {
 398     us_length = htons((short)1);
 399     memcpy(socksreq+2,&us_length,sizeof(short));
 400   }
 401   else {
 402     gss_send_token.length = 1;
 403     gss_send_token.value = malloc(1);
 404     if(!gss_send_token.value) {
 405       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 406       return CURLE_OUT_OF_MEMORY;
 407     }
 408     memcpy(gss_send_token.value, &gss_enc, 1);
 409
 410     gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
 411                                 GSS_C_QOP_DEFAULT, &gss_send_token,
 412                                 &gss_conf_state, &gss_w_token);
 413
 414     if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_wrap")) {
 415       gss_release_buffer(&gss_status, &gss_send_token);
 416       gss_release_buffer(&gss_status, &gss_w_token);
 417       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 418       failf(data, "Failed to wrap GSSAPI encryption value into token.");
 419       return CURLE_COULDNT_CONNECT;
 420     }
 421     gss_release_buffer(&gss_status, &gss_send_token);
 422
 423     us_length = htons((short)gss_w_token.length);
 424     memcpy(socksreq+2,&us_length,sizeof(short));
 425   }
 426
 427   code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 428   if((code != CURLE_OK) || (4 != written)) {
 429     failf(data, "Failed to send GSSAPI encryption request.");
 430     gss_release_buffer(&gss_status, &gss_w_token);
 431     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 432     return CURLE_COULDNT_CONNECT;
 433   }
 434
 435   if(data->set.socks5_gssapi_nec) {
 436     memcpy(socksreq, &gss_enc, 1);
 437     code = Curl_write_plain(conn, sock, socksreq, 1, &written);
 438     if((code != CURLE_OK) || ( 1 != written)) {
 439       failf(data, "Failed to send GSSAPI encryption type.");
 440       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 441       return CURLE_COULDNT_CONNECT;
 442     }
 443   }
 444   else {
 445     code = Curl_write_plain(conn, sock, (char *)gss_w_token.value,
 446                             gss_w_token.length, &written);
 447     if((code != CURLE_OK) || ((ssize_t)gss_w_token.length != written)) {
 448       failf(data, "Failed to send GSSAPI encryption type.");
 449       gss_release_buffer(&gss_status, &gss_w_token);
 450       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 451       return CURLE_COULDNT_CONNECT;
 452     }
 453     gss_release_buffer(&gss_status, &gss_w_token);
 454   }
 455
 456   result=Curl_blockread_all(conn, sock, (char *)socksreq, 4,
 457                             &actualread, timeout);
 458   if(result != CURLE_OK || actualread != 4) {
 459     failf(data, "Failed to receive GSSAPI encryption response.");
 460     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 461     return CURLE_COULDNT_CONNECT;
 462   }
 463
 464   /* ignore the first (VER) byte */
 465   if(socksreq[1] == 255) { /* status / message type */
 466     failf(data, "User was rejected by the SOCKS5 server (%d %d).",
 467           socksreq[0], socksreq[1]);
 468     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 469     return CURLE_COULDNT_CONNECT;
 470   }
 471
 472   if(socksreq[1] != 2) { /* status / messgae type */
 473     failf(data, "Invalid GSSAPI encryption response type (%d %d).",
 474           socksreq[0], socksreq[1]);
 475     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 476     return CURLE_COULDNT_CONNECT;
 477   }
 478
 479   memcpy(&us_length, socksreq+2, sizeof(short));
 480   us_length = ntohs(us_length);
 481
 482   gss_recv_token.length= us_length;
 483   gss_recv_token.value=malloc(gss_recv_token.length);
 484   if(!gss_recv_token.value) {
 485     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 486     return CURLE_OUT_OF_MEMORY;
 487   }
 488   result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 489                             gss_recv_token.length,
 490                             &actualread, timeout);
 491
 492   if(result != CURLE_OK || actualread != us_length) {
 493     failf(data, "Failed to receive GSSAPI encryptrion type.");
 494     gss_release_buffer(&gss_status, &gss_recv_token);
 495     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 496     return CURLE_COULDNT_CONNECT;
 497   }
 498
 499   if(!data->set.socks5_gssapi_nec) {
 500     gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
 501                                   &gss_recv_token, &gss_w_token,
 502                                   0, GSS_C_QOP_DEFAULT);
 503
 504     if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_unwrap")) {
 505       gss_release_buffer(&gss_status, &gss_recv_token);
 506       gss_release_buffer(&gss_status, &gss_w_token);
 507       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 508       failf(data, "Failed to unwrap GSSAPI encryption value into token.");
 509       return CURLE_COULDNT_CONNECT;
 510     }
 511     gss_release_buffer(&gss_status, &gss_recv_token);
 512
 513     if(gss_w_token.length != 1) {
 514       failf(data, "Invalid GSSAPI encryption response length (%d).",
 515             gss_w_token.length);
 516       gss_release_buffer(&gss_status, &gss_w_token);
 517       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 518       return CURLE_COULDNT_CONNECT;
 519     }
 520
 521     memcpy(socksreq,gss_w_token.value,gss_w_token.length);
 522     gss_release_buffer(&gss_status, &gss_w_token);
 523   }
 524   else {
 525     if(gss_recv_token.length != 1) {
 526       failf(data, "Invalid GSSAPI encryption response length (%d).",
 527             gss_recv_token.length);
 528       gss_release_buffer(&gss_status, &gss_recv_token);
 529       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 530       return CURLE_COULDNT_CONNECT;
 531     }
 532
 533     memcpy(socksreq,gss_recv_token.value,gss_recv_token.length);
 534     gss_release_buffer(&gss_status, &gss_recv_token);
 535   }
 536
 537   infof(data, "SOCKS5 access with%s protection granted.\n",
 538         (socksreq[0]==0)?"out gssapi data":
 539         ((socksreq[0]==1)?" gssapi integrity":" gssapi confidentiality"));
 540
 541   conn->socks5_gssapi_enctype = socksreq[0];
 542   if(socksreq[0] == 0)
 543     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 544
 545   return CURLE_OK;
 546 }
 547 #endif
 548
 549 #endif /* CURL_DISABLE_PROXY */